So, it seems every 3/16” hole in the longeron gets counter sunk. This includes the holes for the skin and canopy deck. I typically counter sink holes that a dimple will fit into, 4 clicks deeper then flush.
Image 4 I’m pointing to 2 holes that were match drilled through the canopy deck. The canopy deck then gets trimmed and these 2 holes will get rivets that need to fit flush. So, these 2 holes are not 4 clicks deeper then flush.
